This project investigates how rhesus monkeys and other nonhuman primate species born and raised under different laboratory conditions adapt to placement into environments that contain specific physical and social features of the monkey's natural habitat. Adaptation is assessed by examining behavioral repertoires and by monitoring a variety of physiological systems in these subjects, yielding broad-based indices of relative physical and psychological well-being. The responses of subjects to experimental manipulation of selected features of their respective environments are also assessed in similar fashion. Whenever possible, field data are collected for appropriate comparisons. An additional focus is on investigating the cognitive, behavioral, and social processes involved in adaptation to new settings or circumstances. This past year we continued to monitor maternal and fetal heart rate and blood pressure throughout the third trimester of pregnancy in several rhesus monkey females who had been surgically implanted with indwelling catheters that enabled us to record these measures online continuously via a tethering device that permitted unimpeded locomotor and exploratory activity within the caging unit. Each pregnant female subsequently successfully delivered an infant who exhibited normal neurological and behavioral postnatal development. Analyses of the prenatal data collected to date were focused on changes in maternal and fetal heart rate and blood pressure following two types of short-term experimental manipulations ? cage restraints and presentation of food treats, respectively, each of which reliably produced comparable short-term increases in maternal heart rate. Significant increases in maternal heart rate in the context of cage restraint were associated with concomitant increases in both maternal and fetal blood pressure and significant decreases in fetal heart rate, whose recovery to baseline values essentially tracked those of maternal heart rate (albeit in the opposite direction). In contrast, significant increases in maternal heart rate following presentation of food treats were not associated with any significant changes in maternal blood pressure or in either fetal heart rate or blood pressure. This past year we also expanded our initial efforts to determine if rhesus monkey neonates are capable of ?imitating? specific facial expressions and hand movements directed toward them by a human ?model? in their initial days of life. Such early imitative capabilities have been reported for human neonates, and they are thought to be reflexively mediated by ?mirror? neurons, a recently characterized class of visual-motor neurons found in Area F5 of the ventral premotor cortex. We found that some (but not all) of the newborns tested were able to mimic specific facial expressions involving differential mouth and tongue movements, but not until their second or third day of life. Interestingly, those infants who demonstrated this imitative capacity spent significantly more time visually focusing on facial stimuli on Day 1 than those who did not exhibit any imitative behaviors on subsequent days. We are now carrying out follow-up behavioral observations and biological sampling of these infants to determine if individual differences in their early imitative capabilities are predictive of individual differences in their biobehavioral functioning throughout subsequent development. In addition, we completed and published the results of a study in which some nursery-reared rhesus monkey infants (?masters?) were given operant control over access to highly desirable food treats, whereas other nursery reared infants (?yoked controls?) received the same treats in the absence of any control. Analyses of behavioral and neuroendocrine data collected both in the infants? home cages and in a novel environment indicated that the ?master? subjects engaged in more exploratory and less anxious-like behavior, and had lower levels of HPA activity, than their yoked control counterparts. Additional analyses of CSF monoamine metabolite concentrations obtained throughout the study are currently underway. Analyses of immunological data collected in another long-term prospective longitudinal study of free-ranging rhesus monkeys residing on the island of Cayo Santiago in Puerto during the annual veterinary trapping of monkeys revealed significant relationships between measures of immune system and HPA axis functioning and maternal dominance status in juvenile subjects. Monkeys whose mothers were low-ranking within their natal social groups exhibited higher cytotoxicity, greater numbers of C8 and C16 Raij targets, and higher concentrations of plasma cortisol than offspring of more dominant mothers. These findings demonstrate that differences in maternal rank can have significant consequences not only for their offspring?s social and emotional development but also for their immune and adrenocortical functioning. A final series of studies investigated the relationship between social dominance ranking and food consumption as a function of food novelty and relative accessibility in a group of tufted capuchin monkeys. High-ranking group members consumed significantly more food that was easily accessible than portions that were hidden from view, whereas the reverse was true for low-ranking subjects. Rates of aggressive threats by high-ranking monkeys toward lower-ranking individuals were inversely related to the amount of food consumed by low-ranking group members. Thus, although tufted capuchin monkeys have been described as a relatively peaceable species (at least compared with rhesus monkeys) and readily share food in a variety of naturalistic and captive situations, there are dominance-related differences in food consumption that appear to be mediated by differences in the relative occurrence and direction of social threat behavior. However, despite these obvious social influences, their behavior in restricted food choice situations appears to be motivated more by the experience of frustration than by aversion resulting from perceived social inequality.